The process I’m using to remove rust with this jig is called electrolysis. It involves the passing of low voltage DC current between the part and an electrode, though an electrolyte solution (in this case water and washing soda). I’m not one to explain the science part behind this, I barely understand it myself, but there’s plenty of information on it on the internet.
First thing I need a container to hold the electrolyte and for the base for the jig. A clean plastic bucket is ideal for this as it’s mostly inert, non conductive and free. I’ve seen various takes at this, but most are basically a plastic container in various shapes and sizes.
Then a DC power source, in the video I’ve used an old 12V 1 Amp car charger, but it was struggling and I later replaced it with a 12V 3 Amp laptop charger that works great for a jig of this size. It does not warm a bit, it removes rust fast and is also fully encased in a plastic case, which makes it feel a bit safer.
As electrolyte I use washing soda (Sodium carbonate, Na₂CO₃). It’s a basic detergent and can be found in most countries. In the states Arm&Hammer is a common brand. Not to be confused with other types of soda, like baking soda or caustic soda, which could be very dangerous!
A plain iron electrode is needed and I used some leftover sheet metal I had. I’ve seen some people use rebar or other iron scraps. The important thing is that it needs to be plain iron, not treated in any way, not stainless, not galvanized and in no case any other metal. Using anything than iron might release harmful gases.
In time this electrode will get covered in rust, but I washed mine with a wire brush after each use and it looks like it will hold for a long time. The round shape helps with rust removal, since it’s mostly a line of sight process. People that used rebar had multiple pieces of them placed around the inside of the bucket to form a circle connected with wire above the water level.
The parts to be derusted are hung from a wood scrap piece using iron wire. Again the use of any other metal wire is dangerous. The wood acts as an insulator between the two poles so it should not be wet. Plastic pipe could also be used.
When the jig was ready I filled it with water and added two small cups of washing soda.
Then the parts were completely submerged in the water and connected to the 12 Volt power supply. Negative to the parts and positive to the scrap iron. The charger was not plugged in when I did this. Only when all things were set up I started the power source.
While working the jig releases some flammable gases so I worked outside. I also kept an eye on it for the whole time, since the charger was getting real hot.
After an hour the parts were done. They are no longer covered in rust, just a black residue that is easily brushed off. This part was a bit controversial in the video, since some people did not see what’s the advantage of electrolysis if I had to use the wire brush too. But there’s a huge difference in the rust and the black residue. The rust is attached to the part and almost impossible to remove by hand with a small brush like that, while the black thing is almost like dirt. Soft and easy to clean. Basically I washed the parts, did not put any effort in the brushing and was done in less than five minutes.
The results were above my expectations and this jig keeps surprising me every time I use it.
This is not the only way to remove rust. I know. I got tired of the alternatives suggested in the comments, again and again, like it’s forbidden to do something differently. I wonder, if they see a video with a guy using a table saw they keep suggesting him to use a hand saw or band saw or whatever?
Mainly two other methods came up again and again: vinegar and wire brushes. Both have advantages and disadvantages. Vinegar (like most acids) is great for small parts, but for large parts, like a lathe bed or car body it’s impractical to buy tons of it. Wire brush is fast but rough and won’t go into tight corners or holes. Also it’s too noisy and messy for my taste. But it is fast and practical in some applications.
Please let me know in the comments below if you need more things cleared about this video.
WARNING! This is not a tutorial, it’s just the way I did this jig, for my personal use. I’m not teaching or encouraging you to do something stupid like this! We’re talking water and electricity, chemicals, rusted objects and hazardous gases! Dangerous stuff! Use vinegar, it works and it’s safer.